RESUMO
We observe that gold atoms deposited by physical vapor deposition onto few-layer graphenes condense upon annealing to form nanoparticles with an average diameter that is determined by the graphene film thickness. The data are well described by a theoretical model in which the electrostatic interactions arising from charge transfer between the graphene and the gold particle limit the size of the growing nanoparticles. The model predicts a nanoparticle size distribution characterized by a mean diameter D that follows a D proportional, variant m(1/3) scaling law where m is the number of carbon layers in the few-layer graphene film.
Assuntos
Cristalização/métodos , Grafite/química , Membranas Artificiais , Modelos Químicos , Nanopartículas/química , Nanopartículas/ultraestrutura , Nanotecnologia/métodos , Simulação por Computador , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Eletricidade Estática , Propriedades de SuperfícieRESUMO
Graphene oxide membranes up to 2000 microm(2) in size can be synthesized with 90% yield in bulk quantities through a microwave-assisted chemical method. Membranes are readily visualized on an oxidized silicon substrate, which enables efficient fabrication of electronic devices and sensors. Field effect transistors made of the membrane show ambipolar behavior, and their conductivity is significantly higher than previously reported values.
Assuntos
Grafite/química , Óxidos/química , Hidrazinas/química , Microscopia de Força Atômica , EspectrofotometriaRESUMO
UNLABELLED: Gene expression microarrays and oligonucleotide GeneChips have provided biologists with a means of measuring, in a single experiment, the expression levels of entire genomes under a variety of conditions. As with any nascent field, there is no single accepted method for analyzing the new data types, with new methods appearing monthly. Investigators using the new technology must constantly seek access to the latest tools and explore their data in multiple ways. The functional genomics data pipeline provides an integrated, extendable analysis environment permitting multiple, simultaneous analyses to be automatically performed and provides a web server and interface for presenting results. AVAILABILITY: Source code and executables are available under the GNU public license at http://bioinformatics.fccc.edu/
